Carrier synergistic effect of iron based catalysts for CO hydrogenation to lower olefins

Three types of catalyst samples, namely alumina carried Fe/K, zinc aluminate carried Fe/K, and (zinc aluminate + alumina) composite carried Fe/K, were prepared under calcination conditions of 350 ºC. The catalysts were characterized by XRD, ICP-OES, N₂ physical adsorption, field emission electron microscopy as well as CO₂-TPD. The performances of the catalysts in CO hydrogenation were tested in a fixed bed reactor. The results show that under similar conversions, the C₂⁼–C₄⁼ hydrocarbon selectivity of the prepared (zinc aluminate + alumina) composite carried Fe/K catalyst can reach 5 times that of the prepared alumina carried Fe/K catalyst and 9 times that of the prepared zinc aluminate carried Fe/K catalyst, exhibiting a typical synergistic effect based on carrier composition. The basis for this synergistic effect is the significant difference in base sites on the catalyst surface.